RU2164517C1 - Method of preparing multifunctional additive for lubricating oils - Google Patents

Abstract

FIELD: organic synthesis and lubricants. SUBSTANCE: additive is prepared by interaction of dialkyldithiophosphoric acid, wherein alkyl is linear or branched alkyl having 4-8 carbon atoms, with zinc oxide in presence of aliphatic alcohol, 2-mercaptobenzothiazole, and water at 80-95 C followed by modifying formed products with boric acid at 90-110 C. The following molar ratio should be observed: dialkyldithiophosphoric acid : zinc oxide : alcohol : water : 2-mercaptobenzothiazole : boric acid = 1:(0.6- 0.75):(0.10-0.2): (0.2-0.8): (0.015-0.06): (0.05-0.1). Aliphatic is 2- ethylhexanol or mixture of aliphatic C5-C8-alcohols. Resulting dithiophosphate additive contains more than 80% principal material. EFFECT: improved tribological and antioxidant properties of doped lubricating oil. 3 cl, 4 tbl, 5 ex

Description

 The invention relates to the field of oil refining and petrochemicals, in particular to a method for producing a multifunctional additive for lubricating oils.

 It is known that when developing a lubricant composition, the greatest attention is paid to the selection of additives capable of protecting metal friction surfaces. Due to their chemical structure, they form a surface film, capable of withstanding the conditions of various friction regimes, without breaking, withstand high loads, including re-variable ones, and ensure smooth operation of machines and mechanisms. Therefore, among the wide range of antiwear additives, it is zinc dithiophosphates that have found the greatest application, and this is primarily due to their ability to exhibit high tribological, anticorrosive, antioxidant and anti-pitting properties.

 Foreign additive manufacturing companies offer a wide range of dithiophosphates, both zinc dithiophosphates proper with various alkyl radicals with different thermal stability, and the combination of dithiophosphates with other additives of a similar purpose, which leads to an expansion in the range of their action.

 In our country, as well as throughout the world, zinc dithiophosphates have a significant proportion in the range of oil additives. However, the quality of domestic additives is inferior to imported ones and there is practically no production of zinc dithiophosphates with an active component content of more than 80%. This is due to technological difficulties associated with the separation of unreacted zinc oxide and mechanical impurities from additives.

 A limited assortment of dithiophosphates is associated with the absence in our country of high-quality aliphatic alcohols with different lengths of the alkyl group.

 The present invention relates to the development of the synthesis of dithiophosphate type additives with a main component content of more than 80% and improved performance and technological parameters.

 There are various methods for producing zinc dithiophosphates, which are based on the reaction of phosphorization of an aliphatic alcohol and (or) a mixture of alcohols, followed by treatment of the resulting dithioic acid with zinc oxide / Pat. U.S. N 4116871 C. 252 / 32.7E; MKI C 10 mol 1/48, Pat. Germany N 3048087 MKI C 07 F 9/165 /.

 The reaction in the presence of solvents, for example alcohols, surfactants, contributes to the production of compounds with higher thermal stability / Pat. USA N 4215067 C. 260 / 420.9; MKI C 07 F 3/06; Pat. Romania N 81290 MKI C 10 M 1/48 /. It is possible to obtain such compounds using a mixture of dialkyldithiophosphoric and carboxylic acids / Pat. USA N 4417990 C. 252 / 32.7E; MKI C 10 M 1/48 /, and in pretreatment of dithioacid with epoxide / Pat. U.S. N 3213021 C. 252 / 32.7E; MKI C 10 M 1/48 /.

 In the synthesis of zinc dithiophosphates, various promoters are used, such as: mineral acids, for example nitric acid / Pat. U.S. N 4104291, cl. 260-429.9; MKI C 07 F 9/06 /, organic acids and their salts / Pat. U.S. N 3102096, class 252-32.7 /, as well as water / Pat. U.S. N 2824062 /. The increase in antioxidant and anticorrosive properties is achieved by using, as the actual reaction product, derivatives of benzotriazole and zinc dithiophosphate / Pat. U.S. N 4456639 NKI 252-46.7; MKI C 10 M 1/48 /, and the composition of zinc dithiophosphate with derivatives of 2-mercaptobenzthiazole / Pat. U.S. N 4917809 NKI 252-32.7; MKI C 10 M 135/36 /.

 The combination of zinc dithiophosphate with boron-containing compounds leads to an improvement in their anti-pitting properties, while alkali metal borates are used as a boron-containing compound / Pat. U.S. N 4,575,431 NKI 252-32.7E; MKI C 10 M 137/10 /.

или формулы:

где Y - -O; -S; -NH или NR₉, Z-(CR₈) или N;
R₁; R₂; R₃ - водород или алкил C₁-C₁₂; или алкенил C₂-C₂₄;
R₄ может быть радикал -C(R₁₀)= N-CH₂-CH₂, где R₁₀ - водород, алкил C₁-C₁₇, алкенил C₂-C₁₇;
R₅ - это водород или группа -SH или алкил C₁-C₂₂;
R₆ - водород;
R₇ - водород или радикал R₆ и R₇ вместе непосредственно связаны;
R₈ - водород или алкил C₁-C₂₂; или фенил, или R₇ и R₈ вместе карбонил;
R₉ - алкил C₁-C₁₂;
и значение a может быть 0, 1 или 2 и фосфорсодержащего соединения (2) формулы

или

где X; X₁ или X₂ независимо друг от друга кислород или сера;
R₁₁, R₁₂ одинаковые или различные алкильные группы C₁-C₁₂, которые могут содержать -O-; -S-; карбонильные группы, фенил и т.д.;
n - имеет значение 1, 2 или 3;
K имеет значения от 1 до 2, и в случае, когда n или n^* равняется 2, радикалы P¹¹ одинаковые или различные, связаны через гетероатомы X¹ с атомом фосфора;
M есть K-валентный металл, протон или соединение HN⁺R₁₃R₁₄R₁₅,
где R₁₃ - водород, или содержащий группу OH^- алкил C₁-C₃₀;
R₁₄ - водород или алкил C₁-C₃₀;
R₁₅ - водород или алкил C₁-C₇; или алкенил C₂-C₁₇;
M есть K-валентный металл или соединение HN⁺R₁₃R₁₄R₁₅, где R₁₃ - водород, R₁₄, R₁₅ - водород или алкил C₁-C₃₀.Closest to the proposed invention is a method for producing a high-temperature lubricant / Pat. U.S. N 4917809 NKI 252-32.7; MKI C 10 M 135/36 /, according to which the composition of the lubricant contains the actual mineral or synthetic oil and 0.05-5% by weight of a mixture of nitrogen-containing compound (I) of the formula:

or formulas:

where Y is —O; -S; -NH or NR ₉ , Z- (CR ₈ ) or N;
R ₁ ; R ₂ ; R ₃ is hydrogen or C ₁ -C ₁₂ alkyl; or alkenyl C ₂ -C ₂₄ ;
R ₄ may be a radical —C (R ₁₀ ) = N — CH ₂ —CH ₂ , where R ₁₀ is hydrogen, alkyl C ₁ -C ₁₇ , alkenyl C ₂ -C ₁₇ ;
R ₅ is hydrogen or an —SH group or C ₁ -C ₂₂ alkyl;
R ₆ is hydrogen;
R ₇ is hydrogen or a radical R ₆ and R ₇ are directly bonded together;
R ₈ is hydrogen or C ₁ -C ₂₂ alkyl; or phenyl, or R ₇ and R ₈ together are carbonyl;
R ₉ is C ₁ -C ₁₂ alkyl;
and the value of a may be 0, 1 or 2 and a phosphorus-containing compound (2) of the formula

or

where is X; X ₁ or X ₂ independently from each other oxygen or sulfur;
R ₁₁ , R _{12 the} same or different alkyl groups C ₁ -C ₁₂ which may contain —O—; -S-; carbonyl groups, phenyl, etc .;
n is 1, 2 or 3;
K has values from 1 to 2, and in the case when n or n ^* is 2, the radicals P ^{11 are the} same or different, linked via heteroatoms X ¹ to the phosphorus atom;
M is a K-valence metal, proton or compound HN ⁺ R ₁₃ R ₁₄ R ₁₅ ,
where R ₁₃ is hydrogen, or containing an OH group ^is C ₁ -C ₃₀ alkyl;
R ₁₄ is hydrogen or alkyl C ₁ -C ₃₀ ;
R ₁₅ is hydrogen or C ₁ -C ₇ alkyl; or alkenyl C ₂ -C ₁₇ ;
M is a K-valent metal or a compound HN ⁺ R ₁₃ R ₁₄ R ₁₅ , where R ₁₃ is hydrogen, R ₁₄ , R ₁₅ is hydrogen or C ₁ -C ₃₀ alkyl.

The following are used as K-valence metal: Li ⁺¹ ; Na ⁺ ; K ⁺ at K = 1 and at K = 2 - Mg ⁺² ; Ca ⁺² ; Ba ^{+ 2} ; Zn ⁺² . However, Zn ^{+2 is} more preferred.

 The composition indicated in the patent is prepared by simple mixing of the nitrogen-containing and phosphorus-containing components, while their ratio can vary from 10: 1 to 1:10, more preferably from 1: 1 to 1: 3.

 The prepared composition is introduced into mineral oil in a concentration of from 0.05 to 5%, and more preferably from 0.1 to 3.0 wt.%.

 A lubricating oil containing the specified composition exhibits a high level of antiwear properties, while the patent does not provide information on the effect of the lubricating composition on other performance properties, such as antioxidant and anti-petting.

 We propose a method for producing a multifunctional additive for lubricating oils based on zinc dialkyldithiophosphate, which allows to obtain a product that can improve not only the lubricating properties, but also other properties: antioxidant, anticorrosive, anti-pitting, etc.

 Achievable technical result of the present invention is the ability to develop a new multifunctional additive for lubricating oils, the introduction of which in mineral oil improves performance properties - antiwear, anti-friction and anti-pitting.

The specified technical result is provided in the proposed method for producing a multifunctional additive by reacting dialkyldithiophosphoric acid, where alkyl R is normal or isostructure C ₄ -C ₈ , with zinc oxide, in the presence of aliphatic alcohol, 2-mercaptobenzthiazole and water at a temperature of 80-95 ^o C subsequent modification of the resulting products with boric acid.

The process of boric acid treatment is carried out at a temperature of 90-110 ^o C and the following molar ratio: dialkyldithiophosphoric acid: zinc oxide: alcohol: water: 2-mercaptobenzthiazole: boric acid equal to 1: 0.6-0.75: 0.10-0 2: 0.2-0.8: 0.015-0.06: 0.05-0.1.

As an aliphatic alcohol, 2-ethylhexanol, or a mixture of C ₅ -C ₈ alcohols, is used.

 The inventive method is illustrated by the following examples.

Example 1
0.75 moles of zinc oxide, 0.2 moles of water, 0.2 moles of isooctyl alcohol, 0.015 moles of 2-mercaptobenzothiazole are charged into a reactor equipped with heating, a stirrer and a nitrogen bubbler. To this mixture is added mineral oil in an amount of 15% by weight of the weight of the loaded dithioic acid. The resulting mixture was stirred for 30 min and at 80 ^o C was dosed 1 mol iizobutilditiofosfornoy acid, after which the process is carried out refinement for 2 hours at 80 ^o C.

After testing the process, 0.05 mol of boric acid is fed into the reactor, and at a temperature of 110 ^° C, the process is tested for 2 hours. Then, the unreacted alcohol and water are distilled off from the reaction mixture, then the product is filtered.

 The resulting additive is a creamy mass of light brown color, has an alkaline number of 15.5 mg KOH / g; pH 6.66; the content of active elements, wt.%: - zinc 8.9; phosphorus - 7.4; boron - 0.07.

Example 2
0.60 moles of zinc oxide, 0.5 moles of water, 0.2 moles of 2-ethylhexanol, 0.06 moles of 2-mercaptobenzothiazole are charged into a reactor equipped with heating, a stirrer and a nitrogen bubbler. To this mixture is added mineral oil in an amount of 15% by weight of the weight of the charged dithiophosphoric acid. The resulting mixture is stirred for 30 minutes and 1 mol of diisobutyl dithiophosphoric acid is metered in at 80 ^° C, after which the process is refined for 2 hours at 95 ^° C. Then 0.1 mol of boric acid is fed into the reactor and the process is perfected at 90 ^° C. for 2 hours. Next, the unreacted alcohol is distilled off from the reaction mixture, water and then the product is filtered. The resulting additive is a creamy mass of light brown color, has an alkaline number of 7.9 mg KOH / g; pH 6; the content of active elements, wt. %: zinc - 9.2; phosphorus - 8.7 and boron - 0.09.

Example 3
In the conditions of example 2, the method is carried out in the following ratio of reagents: zinc oxide — 0.75 mol; water - 0.3 mol; a mixture of alcohols C ₅ -C ₈ - 0.15 mol; 2-mercaptobenzthiozole - 0.03 mol; mineral oil in an amount of 15% by weight of the weight of diisooctyl dithiophosphoric acid, taken in an amount of 1 mol; boric acid - 0.08 mol.

 The resulting additive is a light brown liquid, has an alkaline number of 19.7 mg KOH / g; pH 6.60; the content of active elements, wt. %: - zinc - 8.2%; phosphorus - 7.0%; boron - 0.1%.

Example 4
In the conditions of example 1, the method is carried out in the following ratio of reagents: zinc oxide — 0.55 mol; water - 0.8 mol; 2-ethylhexanol 0.14 mol; 2-mercaptobenzthiazole - 0.05 mol; mineral oil in an amount of 15% by weight of the weight of isobutylisooctyldithiophosphoric acid, taken in an amount of 1 mol; boric acid - 0.05 mol.

 The resulting additive is a light brown liquid, has an alkaline number of 15.4 mg KOH / g; pH 6.30; the content of active elements, wt. %: zinc - 9.1; phosphorus - 8.2; boron - 0.12.

Example 5
In the conditions of example 2, the method is carried out in the following ratio of reagents: zinc oxide — 0.75 mol; water - 0.5 mol; 2-ethylhexanol - 0.1 mol; 2-mercaptobenzthiazole - 0.03 mol; mineral oil in an amount of 15% by weight of the weight of isobutylisooctyldithiophosphoric acid, taken in an amount of 1 mol; boric acid - 0.05 mol.

 The resulting additive is a light brown liquid, has an alkaline number of 12.5 mg KOH / g; pH 6.2; the content of active elements, wt. %: zinc - 9.0; phosphorus 8.1; boron - 0.1.

 The most famous additive in our country, LZ-1395, manufactured by Lubrizol Corp., was used as a prototype.

 An important technical characteristic in the preparation of dithiophosphates is the possibility of their purification from mechanical impurities and unreacted zinc oxide in the filtration process.

 Table 1 shows the results of experiments on filtering additives prepared in accordance with examples 1-5.

 The conditional filtration rate was used as an evaluation criterion, and the higher the indicator value, the more efficient the specified process.

 As can be seen from (table. 1), all of these additives have a satisfactory filtration rate, although slightly lower than that of the additive obtained using the additive technology LZ-1395.

 All additives obtained are soluble in mineral and synthetic base oils.

 To assess the effectiveness of the synthesized compounds, they were introduced into oils M-11 and ACB-10 at a concentration corresponding to 0.06% in phosphorus.

 To determine the lubricating properties, the following were used: four-ball friction machine, where, in accordance with GOST 9490-75, antiwear and extreme pressure properties of lubricating compositions were determined; Optimol SRV stand, where anti-wear properties were determined at a load of 200 N, as well as anti-friction properties - by changing the friction coefficient.

 To determine the anticorrosive and antioxidant properties, the method of determining the indicated properties was used on a DK-NAMI instrument according to GOST 20502-75.

The essence of the method is to determine the mass loss of the lead (copper) plate and change the structure of the oil, which was tested at a temperature of 160 ^o C for a certain period of time.

 The results of the tests are presented in table. 2 and 3.

 Given in the table. 2 and 3, the data show that in terms of the properties shown, the developed additive according to the above examples is not inferior to the additive LZ-1395.

 At present, the composition of motor oils is selected in such a way as to not only improve the lubricating characteristics of the base oil, but also, if possible, increase the ability of the lubricant to withstand, without collapsing, re-transverse stresses, i.e. ultimately reduce the chipping of metal surfaces experiencing compression deformations - "pitting".

 The study of anti-pitting properties was carried out on a cam-pusher installation using the radioisotope method.

 The effectiveness of the anti-pitting action is determined by the increase in the radioactivity of the oil due to the influx of fatigue wear products containing the radioisotope Co.

 The data are given in table. 4.

 The data table. 4 show the effectiveness of the additive obtained by the proposed method as anti-petting.

 The resulting additive is recommended for use in motor and industrial oils. Depending on the purpose of the oil, the additive is introduced in a concentration of 0.7-1.0%.

The effectiveness of the use of the invention is:
- the possibility of industrial production of dithiophosphate additives with a basic substance content of more than 80%;
- improving the tribological, antioxidant and anti-pitting properties of the lubricant with the introduction of additives in the oil composition.

Claims (3)

1. A method of obtaining a multifunctional additive for lubricating oils by the interaction of dialkyldithiophosphoric acid, where alkyl R is normal or isostructure C ₄ - C ₈ , with zinc oxide, characterized in that the interaction is carried out in the presence of aliphatic alcohol, 2-mercaptobenzthiazole and water at a temperature of 80 - 95 ^o With the subsequent modification of the resulting products with boric acid at a molar ratio of dialkyldithiophosphoric acid: zinc oxide: alcohol: water: 2-mercaptobenzthiazole: boric acid, equal to 1: 0.6 - 0.75: 0.10 - 0.2: 0.2 - 0.8: 0.015 - 0.06: 0.05 - 0.1. 2. The method according to claim 1, characterized in that the treatment with boric acid is carried out at a temperature of 90 - 110 ^o C. 3. The method according to claim 1, characterized in that as aliphatic alcohol use 2-ethylhexanol or a mixture of alcohols C ₅ - C ₈ .

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